A vintage-style, sealed enclosure, 3-way loudspeaker with dome tweeters

marabella

Member
2014-07-19 11:34 am
Hello

Some pictures first:

3W_1.jpg

3W_2.jpg

3W_3.jpg

Eton 11_581_50Hex, Morel EM1308 and ET338
(preliminary) Behringer DCX2496 crossover: 600Hz/24dB-Butterworth and 3000Hz/12dB-Butterworth
bass -3dB at 55 Hz
Costs per LS: approx. 750€


I would like to spare myself any metaphorical sound descriptions here.

The loudspeakers exactly deliver what you can expect from drivers of this quality. I listen to music for hours - completely stress-free, relaxed and absolutely delightfully.

The "sound" immediately reminded me of the Focal "Temptation", which I was totally enthusiastic about in ancient times. This is because of the domes, which do their job well and create an incredibly wide stage.

I can, at a distance of about 4m, easily move 2m to the side, without the spatial representation changing significantly. Classical music lovers should be thrilled and even with 3 people on the sofa this should work wonderfully. With "Oxygene", my ultimate test, the loudspeakers disappeared immediately. Only a few can do that at all.

Very low bass is audible, but due to sealed enclosure quieter. On the other hand, its much drier/contoured. The damping, pi times thumb plus experience, seems to fit and thanks to 2.5l polystyrene filling there is still enough space for fine tuning. Seems superfluous to me at the moment. I can't measure under 200Hz anyway.

Interesting: At 8.5KHz there is a -4dB dip. I found the reason when I converted this frequency to its wavelength - about 4cm. This corresponds to the radius (minus dome) of the tweeter mounting plate. I covered it with paper all around the baffle and the dip disappeared.

The drivers will be set flush with 5mm needle felt, the cabinets and stands are going to be painted neatly and then I'll post more pictures and frequency charts.

It may take some time, because my shoulder hurts a lot :-(.

Until then and many greetings
 

marabella

Member
2014-07-19 11:34 am
Changed low-mid co to 700Hz (600Hz were a bit tight) and mid-high characteristic to 18dB Butt.

Morel.jpg

Quick and dirty put the mic 1m in front of the LS.
- blue - with dip at 8,5KHz
- green - quickly set up a filter on the DCX. OMG, that's easy.

Please ignore everything below 200Hz. It's my listening room.
 

marabella

Member
2014-07-19 11:34 am
If it sound right, it doesn't really matter much, but do you guys think there would be benefits by loosing outer parts of mounting plates, to make it possible to group drivers closer? Might be posible to drill resessed mounting holes right outside the magnets diameters.
Cheers

It depends. Sometimes the mounting plate is fixing the diaphragm - Monacor DT-254. Sometimes the mounting plate has a special design as an initial wave guide - most ribbon tweeters.

And generally spoken: I guess you'll barely hear any difference.

Why not cut/file out an appropriate circle segment either in the mid or high? Some commercials do that.
 

marabella

Member
2014-07-19 11:34 am
.. frequency response:

Morel.jpg

MOREL-FR.jpg

Blue curve: naked Baffle
Green curve: baffle covered with felt

So, in this configuration, it meets my expectations.

I'm not completely satisfied with the bass tuning yet.
I have currently added the 2.5l polystyrene volume with damping unchanged. There's a difference but it's hard to quantify it by ear.

Now I am tempted to develop a passive crossover. Let's see.